New tubes - Problem with balance

[Mazash]

Hey all,

I've just acquired JJ tubes (sorry I forgot the model) and my ESX's just became another machine. Really.
But I haven't found any way to balance them correctly. Whichever the settings of the two black knobs are, my test sound (a simple sine wave) keeps sounding louder on the right...

Any suggestion please ?

thanks a lot

EDIT :

I've read somewhere on this forum about a tip concerning a special cable with a special tweaking mode on the electribe, but as my english is poor and the post has no picture to help, I don't understand the explanation.

Here are the instructions for tube calibration.
I'm assuming that its OK to put in public domain as these were sent to me to save sending the unit to the service department.
There is a picture and a diagram of the cable that the instructions refer to but I don't know how to paste photo's or diagrams on the forum.

The cable referred to is a balanced (stereo) jack running into a mono (unbalanced) jack. The tip and end ring of the stereo cable are joined together at the mono end tip with the sleeves remaining the same. (I hope that makes sense - ignore my earlier post where I mention a Y cable - it's not).



EMX-1/ESX-1 Tube Calibration
１．Connect the stereo plug of the cable (see fig.) to PHONES and the monaural plug to
INPUT.
2. While pressing ERACE and STEP EDIT, turn the power on. “Valv Wup” is
indicated as stand-by for pre-heating, and also the waiting time is indicated.
Set up the volume knob and switches as follows:
MASTER VOLUME : MAX
TUBE GAIN : MIN
AUDIO IN LEVEL : MAX
MIC/LINE : MIC
3. “Ajst (L)” and a 4 digits figure are indicated in the LCD. If the value is leas than
0010, the test is O.K.. Press the 16 knob at the right bottom. If the value is over it, it is
required to adjust the valve. Adjust the variable resistors which correspond to the
channels referring to the photo below.





4. As well as　“Ajst(L)”, “Ajst (R)” and a 4 digits figure are indicated in the LCD.
If the value is leas than 0010, the test is O.K.. Press the 16 knob at the right bottom. If
the value is over it, it is required to adjust the valve. Adjust the variable resistors
which correspond to the channels referring to the photo above.
5. Once the balance of L/R is automatically adjusted, “ValvGMax GainMx” is
indicated in the LCD. Turn the TUBE GAIN knob to MAX, and press the 16 knob.
6. Check the L/R balance of TUBE GAIN MAX, and return to the normal mode.[/img]

[hazabikit]

That happened to me, too -- when I put new tubes in, the audio was panned too far to the right. I fixed it by adjusting the little screws next to the tube sockets.

I used a flat-head screwdriver, and turned them each about 1/8 turn to the left... listen to the 4x4 "Init" beat with a pair of headphones while you do this, and you'll be able to hear the sound move back to the center.

[Mazash]

thanks for your reply

That's what I've done.

I tried with the 4x4 beat, a sine wave, a complete track, etc... With headphones, monitors, helped by the vu-meters of my mix-table.

I checked the cables, etc...

the point is that the screws never bring the sound back to the center. I turn it in both ways, there's a slight difference of panning but the right side is always louder.

[Mazash]

Well, I've been at the store where I bought the tubes, and they advised me to swap them.
Finally, the problem has been solved ! I tweaked a bit the black knobs and had no problem to make the balance.

Hope it'll help some. Thanks for your help.

[Laxiton]

I have just acquired a ESX, the main volume pot gave some noise on the left but after some contact spray all was alright.

BUT the left is a lot more quiet. Is it normal that even after exchanging the right tube with the left, the left is still more silent? I would've expected the left to become the loudest.

Anyone some experience with this?

[Electromachines]

The best way of checking balance issues is the korg factory check method (as mentiond here and on another thread)If you are unable to get hold of the cable (stereo trs jack - mono jack) use your ears and adjust the pots that sit next to the valves a little at a time.

The trouble with valves is not only volume, but frequencies drop too. I was getting slightly nicer rounded bass tones on the right side.
Every valve is slightly different so it is VERY important you get a MATCHED AND BALANCED pair,at least then you will have a very good chance of getting the balance right on test.

[Laxiton]

It's true I get a warmer sound turning those little knobs to the right but if the tubes were at fault, wouldn't switching them change the balance to the other side?

I'm really thinking the potentiometer is at fault, after all the low volume is always left no matter how the tubes are placed and there's always a slight distortion (only left as well no matter what).

Like suggested here http://www.korgforums.com/forum/phpBB2/ ... alibration